I recently saw a website for a DIY garage in WA. Opening hours are 8am to 8pm, 7 days a week, and they offer free storage over night if your work isn't finished at closing time.
Their rate is $22/hour, so it will cost $264 to fix your car there a full day. It includes free heavy tools such as hoist and engine lifter, gearbox jack, compressed air.
In other words it is quite costly to be at a DIY place if you do it every weekend.
In the past when I lived in a CBD townhouse, I went for a drive in rural areas around, and I knocked on doors at places where the owners already had multiple cars in parts around their houses, so after about 5 attempts I was lucky and met a nice guy that was willing to keep a couple of my cars for monthly cash payments. I had some cars there for some years. I had a WRX STi wreck there for a while and it got broken into and stripped by some idiot, the
ECU missing, instrument cluster forced out, headlights forced out, but most of the time it went well.
After that I purchased a shipping container and had my projects stored inside that.
The problem is security, and it could also be a problem for the property owner if a place starts looking like a 'wrecking yard' or 'repair business'.
Cheers,